Handheld metal detectors use electromagnetic induction principle, the use of alternating current through the coil, resulting in a rapidly changing magnetic

Field. The magnetic energy inside the metal object can be induced eddy currents. Eddy current will generate a magnetic field, upside down affect the original

To the magnetic field, triggering detector sends song. The accuracy and reliability of the metal detector depends on the electromagnetic transmitter frequency

Rate stability, the general use from 80 to 800 kHz operating frequency. The lower the operating frequency of detection of iron

We can be better; the higher the frequency, the detection performance of high-carbon steel, the better. Sensitivity of the detector with detection range

Increases decreases induced signal depends on the metal particle size and electrical properties.